Expandable prosthetic valve having anchoring appendages

ABSTRACT

A heart valve prosthesis includes an expandable prosthetic valve including three valve leaflets coupled to an anchoring structure. The anchoring structure includes an annular member and a plurality of arms movably coupled to the annular member at one end. The free ends of the arms extend radially away from the prosthesis toward a valve annulus. The arms are configured to fit in a space defined between an open native valve leaflet and a wall of a valve sinus. The arms are sufficiently resilient such that they resist downward movement in response to pressure exerted on the prosthesis, facilitating anchorage and stabilization of the prosthesis at the implantation site.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Provisional Application No.61/140,494, filed Dec. 23, 2008, entitled “Expandable Prosthetic ValveHaving Anchoring Appendages,” which is herein incorporated by referencein its entirety.

BACKGROUND

The present invention relates to cardiac-valve prostheses. Morespecifically, the present invention is directed to a prosthesis amenableto a minimally-invasive implantation procedure having a stent-likeanchoring structure. These prostheses (often referred to as percutaneousvalves) typically include an anchoring structure, which is able tosupport and fix the valve prosthesis at the implantation site, andprosthetic valve elements, generally in the form of leaflets or flaps,which are connected to the anchoring structure and configured toregulate blood flow. The prosthetic valve may be introduced into aposition corresponding to the natural annulus and deployed in situ bydivaricating the native valve leaflets (or following removal of thenative leaflets).

SUMMARY

The present invention, according to one exemplary embodiment, is a valveprosthesis for implantation in or near a human heart at a valve siteincluding one or more valve sinuses. The prosthesis includes ananchoring structure comprising an annular outflow member, an annularinflow member, and a plurality of arms each coupled at one end to theannular outflow member, the arms having a first end coupled to theannular outflow member and a second end configured to contact a base ofthe valve sinus. It further includes a plurality of leaflets coupled tothe anchoring structure and adapted to substantially allow blood flow ina first direction and to substantially prevent blood flow in a seconddirection. The annular outflow member has an expanded position generallyconfigured to engage a vessel wall at a location distal to the valvesinus, and at least one of the plurality of arms is shaped to engagesubstantially an entire longitudinally extending surface of the valvesinus.

According to another embodiment, the present invention is a valveprosthesis having an plurality of valve leaflets coupled to an anchoringstructure. The anchoring structure includes one or more anchoring armsadapted to substantially engage a valve sinus. The anchoring armsinclude a free end adapted to contact a base of the valve sinus adjacentone or more native valve leaflets.

The present invention, according to yet another embodiment, is a methodof implanting an expandable valve prosthesis at a target implantationsite in or near a patient's heart, the implantation site including atleast one valve sinus. The method includes providing a heart valveprosthesis including a prosthetic valve having three leaflets coupled toan anchoring structure, the anchoring structure including an annularmember coupled to a plurality of arms having first and second ends, suchthat the second ends are not directly coupled to the anchoringstructure; transitioning the prosthesis from an expanded position to acollapsed position; delivering the prosthesis to a target implantationsite within a patient's heart in a minimally invasive manner;facilitating expansion of the prosthesis including the arms; andpositioning the second ends of the arms in a space defined between anative valve leaflet and a sinus wall.

According to a further embodiment, the present invention is a kit forimplanting a heart valve prosthesis at an implantation site within apatient's heart. The kit includes an expandable heart valve prosthesisincluding an expandable prosthetic heart valve having three leafletscoupled to an anchoring structure, the anchoring structure including anannular outflow member and a plurality of arms movably coupled to theannular member, wherein the arms are configured to contact a base of avalve sinus adjacent an open native heart valve leaflet; a crimping tooladapted to transition the prosthesis from an expanded position to acollapsed position; and a delivery catheter adapted to deliver theprosthesis to the implantation site.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an aorta of the human heart having animplanted expandable heart valve prosthesis according to an embodimentof the present invention implanted within or adjacent to an aorticvalve.

FIG. 2 is a top perspective view of an expandable prosthetic valveincluding an anchoring structure according to an embodiment of thepresent invention.

FIG. 3 is a perspective view of an expandable prosthetic valve includingan anchoring structure according to another embodiment of the presentinvention.

FIG. 4 is a top, schematic view of an expandable prosthetic valveimplanted at an implantation site according to an embodiment of thepresent invention.

FIG. 5 is a flow chart of a method of implanting an expandableprosthetic heart valve according to various embodiments of the presentinvention.

FIG. 6 is a schematic view of a delivery system for implanting anexpandable prosthetic valve according to various embodiments of thepresent invention.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of an expandable prosthetic valve 2,according to an embodiment of the present invention. As shown in FIG. 1,the prosthetic valve 2 includes an anchoring structure 6 havinganchoring arms or appendages 10. The prosthetic valve 2 is shownimplanted within or adjacent an aortic annulus 16 of an ascending aorta18, which is coupled to the left ventricle of a heart. During normaloperation, the left ventricle pumps blood out of the heart through theaortic annulus 16 and into the ascending aorta 18 (as indicated by thearrows in FIG. 1). The prosthetic heart valve 2 is suitable forimplantation within or adjacent a valved intraluminal site usingendovascular delivery techniques known to those of skill in the art.Such a site includes, for example, the aortic valve 16 (as shown in FIG.1), the tricuspid valve, the pulmonary valve, and the mitral valve of apatient's heart. The prosthetic heart valve 2 is implanted within thevalved intraluminal site such that the native valve leaflets 19 are heldin the open position and the prosthetic heart valve 2 is expanded tobear against a vessel or sinus wall, e.g., the Valsalva sinus (VS). Theprosthetic valve 2, includes an annular proximal (or inflow) ring 20located at or near the native valve annulus and an annular distal (oroutflow) ring 21 generally located at an opposite end of the valve(i.e., away from the valve annulus).

FIG. 2 is a top perspective view of a prosthetic valve and FIG. 3 is aside perspective view of a prosthetic valve according to variousembodiments of the present invention. As shown in FIGS. 2 and 3, each ofthe expandable prosthetic valves 2 includes a valve sleeve 22 includingthree leaflets 24 a, 24 b, and 24 c coupled to the anchoring structure6. The valve sleeve 22 may be constructed according to varioustechniques known in the art. The valve sleeve 22 includes a base portion30 with an overall annular pattern, designed to extend from the lowerportion of the prosthetic valve 2, which at the implantation site, is ina position proximal to the valve annulus. Three pleat formations 32extend distally from the base portion 30. The valve leaflets 24 a, 24 band 24 c extend between adjacent pleat formations 32. Each valve leaflet24 a, 24 b and 24 c has a proximal edge with an arched pattern thatextends from the base formation 30 and along two adjacent pleatformations 32, and a distal edge that extends towards a central orificeof the prosthesis, so as to cooperate with the edges of the other valveleaflets in a coapting fashion.

As is generally known by those of ordinary skill in the art, inoperation, as blood flows out of the ventricle and through theprosthetic valve 2, the compliant valve leaflets 24 a, 24 b, 24 c areadapted to deform and move towards the support structure 6 to allow freeflow of the blood through the prosthesis. When the pressure gradient,and hence the direction of flow, of the blood through the prosthesis isreversed (i.e., blood is flowing into the left ventricle), the coaptingedges of the valve leaflets 24 a, 24 b, 24 c move towards each other(e.g., contact each other) such that the leaflets substantially closeand thus prevent the flow of the blood through the prosthesis 2. In someembodiments of the present invention, the valve leaflets 24 a, 24 b, 24c are made in such a way as to assume, in the absence of externalstresses, the closed configuration. In various embodiments, as shown inFIG. 3 the valve sleeve 22 includes an annular securing device 36,located at or near a proximal end of the valve, for securing theprosthetic valve 2 to the valve annulus. According to some embodiments,the annular securing device 36 is a sewing ring such as that shown anddescribed in U.S. Pat. No. 5,163,954, which is hereby incorporated byreference.

The anchoring structure 6 is adapted to stabilize and secure theprosthetic valve 2 at an implantation site within a patient's body. Asshown in FIG. 3, the anchoring structure 6 includes an annular outflowmember 52, a plurality of vertical support members 54, and at leastthree anchoring appendages or arms 10 coupled to the annular member 52and adapted to extend radially outward from the support structure 6. Insome embodiments, the arms 10 are movably coupled to the supportstructure such that they can transition from a collapsed position to anextended position. The annular member 52 and the respective arms 10,together with an annular inflow ring 20 facilitate anchoring of theprosthetic valve 2 at the desired implantation site. According to someembodiments, the annular inflow ring 20 is dimensioned to secure thevalve prosthesis against a proximal surface of the valve annulus.According to some embodiments, the prosthetic valve 2 includes a seallocated at or near the proximal end to prevent perivalvular leakage.Such a seal is disclosed, for example, in co-pending, commonly assignedU.S. patent application Ser. No. 11/871,447, filed Oct. 12, 2007,entitled “Expandable Valve Prosthesis With Sealing Mechanism,” which ishereby incorporated by reference.

In some embodiments, as discussed in further detail below, the anchoringstructure 6 can include a plurality of anchoring arms 10 made at leastpartially of shape-memory material (e.g., Nitinol), which enableregulation of the anchoring and support through the control of thememory of the shape-memory material (e.g., by controlling itstemperature). According to other embodiments, the entire anchoringstructure 6 is made from a shape memory material. In still otherembodiments, the anchoring structure 6 can be made of a re-absorbablematerial, whereas the valve sleeve 22 can be constituted by biologicaland/or synthetic tissues, which are in part colonizable orre-absorbable.

During implantation, the prosthetic valve 2 is advanced towards theimplantation site in a radially contracted configuration, with theannular member 52 in a radially collapsed configuration. According tosome embodiments, the annular member 52 has a collapsed diameter ofabout 5 to about 15 mm in the collapsed configuration. Upon delivery tothe target implantation site, expansion of the annular member 52 isfacilitated until it reaches an expanded configuration. According tosome embodiments, the diameter of the annular member 52 ranges fromabout 18 mm to about 30 mm in the expanded configuration.

According to some embodiments, the annular member 52 has an open meshstructure similar to the structure of a stent used for angioplasty. Themesh structure facilitates expansion of the annular member 52 from acollapsed configuration to an expanded configuration similar to themovement of expansion in situ of an angioplasty stent. According to someembodiments, the annular member 52 has a rhomboidal-mesh structure. Inother embodiments, the annular member 52 can be fabricated to have anymesh structure configured to radially expand and collapse in the mannerdescribed above.

According to some embodiments, the annular member 52 is at leastslightly flared outward like an enlarged opening of the flow duct of theblood. This configuration may facilitate positive anchorage of theannular member 52 at the implantation site. In other embodiments, theannular member 52 flares or curves inwardly, such as is described forexample in commonly assigned, co-pending U.S. Publication No.2009/0287296, filed May 13, 2009, entitled “Atraumatic Prosthetic HeartValve Prosthesis,” which is hereby incorporated by reference. Securelyanchoring the prosthetic valve 2 at the implantation site promotesperivalvar tightness, improving the hemodynamics and adapting the linesof blood flow in the ventricular chamber to the flow tube constituted bythe valve sleeve.

As best shown in FIG. 3, a plurality of vertical support members 54 arecoupled at their proximal ends to the annular member 52. The verticalsupport members 54 are configured to support the valve sleeve 22 on theanchoring structure 6. According to some embodiments, the supportmembers 54 include generally flat bars set at an angular distance apartfrom one another by about 120°. In some embodiments, each of thegenerally flat bars forming the support member 54 include a plurality ofapertures or holes formed therein. As shown in FIG. 3, each of the pleatformations 32 embraces one of the support members 54, with the valveleaflets 24 a, 24 b and 24 c extending in a festoon between two adjacentsupport members 54. The generally apertured structure of the supportmembers 54 enables the valve sleeve 22 to be secured to the supportstructure 6 by, for example, suturing stitches according to techniquesknown to those of skill in the art. In the case where flaps of polymericmaterials are used, the flaps can be formed directly on the structure,using techniques such as, for example, dip casting.

Also coupled to the annular member 52 are a plurality of anchoring arms10. As shown in FIGS. 1-4, each of the arms 10 includes first and secondlegs 60, 62 each having a proximal end 64 and a generally U-shapedportion 66 coupled to and bridging between the first and second legs 60,62. The arms 10, in one embodiment, are coupled to the annular member 52such that they are disposed over (e.g., centered with respect to) eachof the support members 54. As shown in FIG. 1, according to variousembodiments, the prosthetic valve 2 is sized and shaped such that theannular member 52 is located at or near a distal-most portion of thevalve. In this embodiment, the prosthetic valve 2 has a length such thatonce implanted at an appropriate site, the annular member 52 ispositioned distal to the valve sinus (VS), while the annular inflowmember 20 is located at or near the native valve annulus 16. Accordingto various embodiments, the anchoring arms 10 extend radially outward asufficient distance to allow a native, stenotic valve leaflet to fitbetween the arm 10 and the corresponding portion of the body of theanchoring structure 6. As shown, the arms 10 also extend from theoutflow ring 21 at the distal end of the valve towards the inflow ring20 at the proximal end of the valve.

Additionally, according to some embodiments, each of the arms 10 ismovably coupled to the annular member 52 such that they are able totransition from a collapsed position suitable for implantation to anextended position. In the extended position, the arms 10 are configuredto anchor and secure the prosthesis at an implantation site. In someembodiments, as shown for example in FIG. 1, the arms 10 extendproximally a sufficient length to engage the base of the valve sinus(VS), generally at or near the intersection of the valve sinus and thenative valve leaflets 19. In this configuration, any force applied tothe distal end of the prosthetic valve 2 is transferred by the arms 10to the base of the valve sinus. The arms 10, thus operate to generallysecure the prosthetic valve 2 at the implantation site adjacent thevalve annulus and prevent undesired movement or migration of the valve.

According to some embodiments, as shown in FIG. 3, the first and secondlegs 60, 62 of each arm 10 are made in the form of struts that extend ina generally sinusoidal fashion, with bends or open loops situated oneither side with respect to an imaginary line extending approximately inthe direction of the overall cylindrical shape of the prosthesis 2. Inother embodiments, the sinusoidal pattern can be obtained with bends oropen loops that extend from one side and from the other with respect toa line that extends in a circumferential direction with respect to theprosthesis. In another embodiment, the first and second legs may have amesh structure extending there between. According to some embodiments,the legs 60 include a bends or loops angled away from correspondingbends or loops on the legs 62, to provide additional anchoring withinthe Valsalva sinus. The bends or loops, for example, may include acurvature adapted to generally match the corresponding portion of theinterior wall of the Valsalva sinus. While the embodiments shown inFIGS. 2-4 have three arms 10, the present invention contemplatesembodiments having more or fewer arms 10. In one embodiment, forexample, the anchoring structure 6 includes six arms 10, two armsassociated with each of the three Valsalva sinuses.

The U-shaped portion 66 extends between and bridges the first and secondlegs 60, 62 of each arm 10. According to some embodiments, the U-shapedportion 66 is integrally formed with each of the legs 60, 62. Accordingto other embodiments, the U-shaped portion 66 is a separate piece weldedto or otherwise attached to each of the legs 60, 62 such that it extendsbetween and forms a bridge between each of the legs 60, 62. According tosome embodiments, the length of the U-shaped portion 66 is selected suchthat the legs 60, 62 are configured to press against and inwardly angledsurface of the inner wall of the Valsalva sinus, such that anchoring isimproved.

The U-shaped portion 66 may be substantially straight, arched, orotherwise bent at the portion extending between the first and secondlegs 60, 62. The U-shaped portion 66 is generally smooth and free fromrough edges such that when it contacts and presses up against tissue atthe implantation site it will not cause trauma at the site. According tosome embodiments, the U-shaped portion 66 has a curved shape configuredto generally match the contours of the base of the valve sinus.Additionally, the U-shaped portion 66 may include a sleeve or otherprotective coating. The sleeve or protective coating may be formed froma biocompatible polymer or polymeric coating. According to furtherembodiments the sleeve or protective coating may include a therapeuticagent, such as a steroid, to reduce inflammation at the implantationsite.

According to some embodiments, as shown for example in FIG. 1, theanchoring arms 10 have an arched or curved configuration, such that thearms 10 generally follow the longitudinal contours of the patient'svalve sinus wall (i.e., from the start of the valve sinus near the valveannulus extending distally away from the valve annulus to the end of thesinus at the vessel wall). In these embodiments, the anchoring arms 10substantially conform to or engage the sinus walls so as to ensure firmanchorage in situ of the prosthetic valve 2. Examples of arms or supportstruts configured to substantially engage the sinus walls are shown inco-pending, commonly assigned U.S. patent application Ser. No.11/066,346, filed Feb. 25, 2005, entitled “Minimally-InvasiveCardiac-Valve Prosthesis” and U.S. patent application Ser. No.11/352,021, filed Feb. 10, 2006, entitled “Cardiac-Valve Prosthesis,”both of which are hereby incorporated by reference.

According to the embodiment shown in FIGS. 1 and 3, the legs 60, 62 ofthe U-shaped portion 66 define a double curvature. The first curve,which is convex with respect to a longitudinal centerline of the valve2, extends outwardly away from the outflow ring 21 of the anchoringstructure 6. This first curve has a radius of curvature, R1, selectedsuch that the legs 60, 62 generally conform to the curvature at thedistal portion of the Valsalva sinus. The second curve, which is concavewith respect to a longitudinal centerline of the valve 2, has a radiusof curvature, R2, selected such that the legs 60, 62 generally conformto the curvature of the proximal portion of the Valsalva sinus.

As will be appreciated by those skilled in the art, the aortic root ofthe normal heart includes three aortic sinuses, which are distributed inan approximately angularly uniform way around the root of the arterydistal to the semi-lunar valve (i.e., the aortic or pulmonary valve).According to various embodiments, as illustrated in FIGS. 2-3, theanchoring structure 6 includes three arms 10 set at an angular distanceapart of about 120° with respect to a longitudinal axis of theprosthetic valve 2. According to other embodiments, the prosthetic valve2 includes more or fewer anchoring arms 10 to match human anatomiesincludes more or fewer aortic sinuses.

According to various embodiments, the anchoring arms 10 are shaped suchthat, in the expanded configuration, the arms 10 apply an outwardlydirected radial force against an inner wall of the Valsalva sinus. Insome embodiments, the arms 10 are configured such that this radial forceis selected to sufficiently anchor that prosthetic valve 10 at theValsalva sinus under operating conditions typically present during thehuman cardiac cycle.

FIG. 4 is a top cross-sectional view of a prosthetic valve 100 implantedat a native aortic valve site, according to an embodiment of theinvention. As shown, and as discussed in detail above, the prostheticvalve 100 can be implanted such that the annular member 152 of theanchoring structure occupies a position distal to the Valsalva sinuses(VS). According to various embodiments, the arms 110 can be arranged andpositioned relative to the sinuses of Valsalva such that each of thearms 110 projects into the respective sinus of Valsalva andsubstantially engages the sinus wall. More particularly, as discussedabove, the arms 110 project into the Valsalva sinus and rest in a spacedefined between an open valve leaflet and the sinus wall. As shown inFIG. 4, each of the arms 110 can be positioned on opposite sides of thecoronary ostia (CO) in the respective sinuses of Valsalva. The valveleaflets 24 a, 24 b, 24 c can be positioned within the lumen for bloodflow formed by the annular member 152 with the support members (notvisible) extending into the lumen by a minimal amount. Uponimplantation, the arms 110 of the anchoring structure engage or bearagainst the walls of the valve sinus at the implantation site, withoutinterfering with the blood flow.

FIG. 5 is a flow chart 200 of a method of implanting an expandable heartvalve prosthesis according to an embodiment of the present invention.First, a valve prosthesis including an anchoring structure, istransitioned from an expanded position to a collapsed position adaptedfor delivery of the prosthesis to an implantation site within apatient's heart (block 210). In various embodiments, the prosthesis isdelivered using any of a variety of known minimally-invasive deliverytechniques. According to one embodiment, the valve is delivered using anoff-pump or beating heart procedure. In some embodiments, a crimpingtool or other similar device known to those of skill in the art, can beused to radially collapse the prosthetic heart valve including theanchoring structure. One such crimping system, for example, is disclosedin co-pending, commonly assigned U.S. patent application Ser. No.11/776,695, filed on Jul. 12, 2007, entitled “Expandable ProstheticValve Crimping Device,” which is hereby incorporated by reference. Afterthe prosthesis has been transitioned from an expanded position to acollapsed position, the prosthesis can be loaded into a deliverycatheter. The prosthesis, according to various embodiments, is deliveredusing a valve delivery system of the type disclosed in U.S. patentapplication Ser. No. 11/851,523, entitled “Prosthetic Valve DeliverySystem Including Retrograde/Antegrade Approach,” and/or U.S. patentapplication Ser. No. 11/851,528, entitled “Fluid-Filled Prosthetic ValveDelivery System,” both filed Sep. 7, 2007, both of which are herebyincorporated by reference.

The prosthesis is then delivered to a target implantation site within apatient's heart using known methods and techniques in a minimallyinvasive manner (block 220). According to some embodiments, the deliverycatheter is withdrawn facilitating the automatic expansion of theprosthesis including the support structure from its collapsedconfiguration to its expanded configuration (block 230). According tofurther embodiments, an inflatable balloon can be inserted and expandedwithin the prosthetic heart valve facilitating expansion of the valveand the support structure.

Once expanded, an annular outflow ring of the prosthetic valve islocated generally distal with respect to the valve sinus, and an annularinflow ring is located generally at or near the native valve annulus. Inembodiments where the arms are fabricated of a resilient, shape memorymaterial, the arms automatically expand into position such that theygenerally engage the walls of the valve sinus. The arms, according tovarious embodiments, engage a space between a native valve leaflet and asinus wall such that they anchor and secure the prosthesis at theimplantation site. In this configuration, the arms generally resistdownward movement in response to the pressure exerted upon theprosthesis, such that the valve remains at the desired implantation site(block 240).

FIG. 6 is a schematic view of a delivery system 300 for delivering theprosthetic valve 2 to the desired implant location. As shown in FIG. 6,the delivery system 300 is being used to introduce the prosthetic valve2 in the same direction as the blood flow, BF. In other words, as shownin FIG. 6, the delivery system 300 is being introduced into to theValsava sinus (VS) region of the aortic valve through the leftventricle. As shown, the delivery system 300 includes a sheath orcatheter 302, a first deployment element 304, and a second deploymentelement 306. The prosthetic valve 2 is shown in its collapsedconfiguration and is disposed inside the deployment elements 304, 306.As further shown in FIG. 6, in various exemplary embodiments, thedelivery system 300 includes a guidewire or stylet 310 coupled to acentering mechanism 314. The centering mechanism 314 may be used to helpcenter the delivery system 300 in the aorta (AO) during an implantationprocedure. During implantation, the delivery system 300 is used toadvance the prosthetic valve to the desired implant location, forexample, at or near the annulus (A) of the native aortic valve. Oncedisposed at the desired location, the implanting physician may activatethe deployment elements 304, 306, by causing one or both to move back orforth with respect to the prosthetic valve 2, which thereby releases thevalve and allows is to expand radially and contact the wall of theannulus, aorta, and/or valve sinus. According to other embodiments,other delivery systems may be used to implant the prosthetic valve 2.Exemplary delivery systems are disclosed in U.S. patent application Ser.No. 11/612,974, filed Dec. 19, 2006, entitled “System for In SituPositioning of Cardiac Valve Prostheses Without Occluding Blood Flow,”and U.S. patent application Ser. No. 11/612,980, filed Dec. 19, 2006,entitled “Instrument and Method for In Situ Deployment of Cardiac ValveProstheses,” both of which are hereby incorporated by reference.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

1. A valve prosthesis for implantation in or near a human heart at a valve site, the valve site including one or more valve sinuses, the prosthesis comprising: an anchoring structure comprising an annular outflow member, an annular inflow member, and a plurality of arms each coupled at one end to the annular outflow member, the arms having a first end coupled to the annular outflow member and a second end configured to contact a base of the valve sinus; and a plurality of leaflets coupled to the anchoring structure and adapted to substantially allow blood flow in a first direction and to substantially prevent blood flow in a second direction; wherein the annular outflow member has an expanded position generally configured to engage a vessel wall at a location distal to the valve sinus, and wherein at least one of the plurality of arms is shaped to engage substantially an entire longitudinally extending surface of the valve sinus.
 2. The valve prosthesis of claim 1 wherein each of the plurality of arms includes a first leg and a second leg and a U-shaped portion extending between the first and second legs.
 3. The valve prosthesis of claim 1 wherein the arms are configured to secure and stabilize the prosthetic heart valve at an implantation site relative to native heart valve leaflets.
 4. The valve prosthesis of claim 1 wherein the arms are configured to contact a space defined between an open valve leaflet and the sinus wall.
 5. The valve prosthesis of claim 1 wherein the arms comprise a shape memory material.
 6. The valve prosthesis of claim 1 wherein the anchoring structure comprises a shape memory material.
 7. The valve prosthesis of claim 1 wherein the arms and said expandable stent structure are dimensioned so that a native, stenotic heart valve leaflet can fit therebetween.
 8. The valve prosthesis of claim 1 wherein the annular inflow member is dimensioned to secure the valve prosthesis against a proximal surface of the valve annulus.
 9. A method of implanting an expandable valve prosthesis at a target implantation site in or near a patient's heart, the implantation site including at least one valve sinus, the method comprising: providing a heart valve prosthesis including a prosthetic valve having three leaflets coupled to an anchoring structure, the anchoring structure including an annular member coupled to a plurality of arms having first and second ends, such that the second ends are not directly coupled to the anchoring structure; transitioning the prosthesis from an expanded position to a collapsed position; delivering the prosthesis to a target implantation site within a patient's heart in a minimally invasive manner; facilitating expansion of the prosthesis including the arms; and positioning the second ends of the arms in a space defined between a native valve leaflet and a sinus wall.
 10. The method of claim 9 wherein the step of facilitating expansion of the prosthesis further includes inflating a balloon within the prosthesis such that the prosthesis including the arms is transitioned from the collapsed position to the expanded position.
 11. The method of claim 9 wherein the prosthesis is delivered using an off pump procedure.
 12. The method of claim 9 further comprising positioning an annular outflow member of the anchoring structure at a location distal to the valve sinus.
 13. The method of claim 9 further comprising expanding the arms such that the arms contact the wall of the valve sinus along substantially the entirety of a length of the arms.
 14. A valve prosthesis comprising an plurality of valve leaflets coupled to an anchoring structure, the anchoring structure including one or more anchoring arms adapted to substantially engage a valve sinus, the anchoring arms including a free end adapted to contact a base of the valve sinus adjacent one or more native valve leaflets.
 15. The valve prosthesis of claim 14 further comprising a seal disposed between a proximal end of the anchoring structure and a native valve leaflet.
 16. A kit for implanting a heart valve prosthesis at an implantation site within a patient's heart, the kit comprising: an expandable heart valve prosthesis including an expandable prosthetic heart valve having three leaflets coupled to an anchoring structure, the anchoring structure including an annular outflow member and a plurality of arms movably coupled to the annular member, wherein the arms are configured to contact a base of a valve sinus adjacent an open native heart valve leaflet; a crimping tool adapted to transition the prosthesis from an expanded position to a collapsed position; and a delivery catheter adapted to deliver the prosthesis to the implantation site.
 17. The kit of claim 16 further comprising an inflatable balloon adapted to transition the prosthesis from the collapsed position to the expanded position at the implantation site.
 18. The kit of claim 16 in which fingers and said expandable stent structure are dimensioned so that a native, stenotic heart valve leaflet can fit therebetween. 